{"algorithm":"Ed25519","public_key_spki_b64":"MCowBQYDK2VwAyEAoB3/nQ+ZOGE/c5QaBfSyvZf6OHTFk95VWfi2YAPik58=","signed_payload":"Ed25519 over canonical JSON (keys sorted recursively, UTF-8)","headers":{"x-signature":"base64 Ed25519 signature of the response body in canonical form","x-signature-key":"sha256 fingerprint of the SPKI public key","x-signed-at":"ISO timestamp included in signature scope via x-signed-at binding: signature covers canonical(body) + '|' + timestamp"},"verify_hint":"sig = Ed25519.verify(pubkey, canonical(body) + '|' + x-signed-at, x-signature)"}